Figure 1.

Results of experiment 1 (A–C) and experiment 2 (D–F). Subjects responded “yes” or “no” to report if they detected a tactile target stimulus and either pointed at (experiment 1) or moved (experiment 2) the relevant finger to indicate the location of the stimulus. A, D, The percentage correct for detection (hit rate) and localization (a 4AFC judgment). B and E show these scores converted to d′ scores so that performance on the two tasks could be compared appropriately. Clearly, subjects were better at detecting than localizing the stimulus. C, F, Localization accuracy for trials on which the subjects detected the target versus trials when they missed the target. The subjects were much better at indicating the location of targets they detected than targets they missed, although in experiment 1 (C), they performed better than chance at indicating the location of missed targets.